1. Field of the Invention
The present invention relates in general to devices used in video endoscopy. More particularly, the present invention pertains to a new and improved adapter assembly for connecting an endoscope to a video camera head.
2. Description of the Prior Art
The field of video endoscopy to which the present invention generally relates includes medical diagnostic and therapeutic disciplines which utilize endoscopes to penetrate and to view otherwise inaccessible body cavities, with minimal intrusion and surgical procedures. Conventional endoscopes can generally be categorized into two classes, namely rigid endoscopes and flexible endoscopes. Examples of such endoscopic instruments include the laparoscope, cystoscope, arthroscope, ureterscope, bronchoscope, and colonoscope.
The advent of video endoscopy has enhanced the utility of the endoscope significantly. In this regard, the use of video cameras provides visual protection to the surgeon and promotes his or her comfort during the operation. Therefore, the surgeon can now provide the endoscopic surgery comfortably with less fatigue, and the surgical procedure can be performed relatively fast and efficiently.
The adaption of video camera technology to endoscopy imaging requires means for coupling the conventional endoscopes to a video camera head. There have been various types of endoscope couplers which generally include real image forming optics mounted within a sleeve, as well as means for focusing the optics. Exemplary endoscope couplers and other adapters in the field are described in U.S. Pat. Nos. 4,076,018 to Heckele; 4,279,246 to Chikama; 4,344,092 to Miller; 4,355,861 to Sebald; 4,413,278 to Feinbloom; 4,414,576 to Randmae; 4,439,030 to Veda; 4,621,618 to Omagari; and 4,639,772 to Sluyter, et al.; and Japanese Pat. No. 58-21134 to Nishigaki.
An endoscopic system, as defined for reference purposes throughout the following description, generally includes an endoscope, an optical adapter and a video camera head. Before use, the endoscopic system must be sterilized by soaking or immersion in a sterilizing solution, followed by drying and assembly. However, the viewing clarity of the adapter can be hampered by the trapping of residual liquid particles inside the chambers or cavities formed between the adapter and the endoscope, as well as between the adapter and the video camera head.
The endoscopic system is, therefore, amenable to unavoidable condensation of the liquid particles on the optical surfaces of the adapter. Such condensation is generally caused by the high energy and heat emitted by the source of illumination, which heats the proximal metallic portions of the endoscope. The condensation generally takes place on the relatively cool front window of the optical adapter, which offer a lower moisture-pressure gradient than the surrounding metal surfaces. The resulting reduction in clarity can significantly hinder the physician's diagnostic ability and can limit the physician's ability to perform the necessary surgical procedures.
While various techniques and couplers have been employed to minimize the condensation of the residual fluid particles on the cooler viewing optics, none has proven to be entirely satisfactory. One such coupler is described in U.S. Pat. No. 4,611,888 to Prenovitz, et al., and relates in general to a device for coupling a rigid surgical endoscope to a video camera.
However, while the patented device may have been successful in providing a compact coupler, it suffers from various severe drawbacks which render it less than desirably practical or efficient for modern applications. In this regard, the disclosed coupling device includes front and rear sections which are rotatable relative to one another in order to cause a similar rotation of the endoscope relative to the camera head. The device further includes sealing means which tends to reduce the fogging of the viewing optics. By using the disclosed coupler, the soaking process of the endoscopic system is accomplished as a unitary arrangement.
However, the patented coupler cannot be used readily in arthroscopic procedures or such other similar endoscopic surgeries which require the interchangeability of endoscopes during the surgical procedure. In fact, the disconnection of the patented coupler from the endoscope during the surgical procedure can expose the image forming optics of the endoscopic system to fluids surrounding the surgical wound. Therefore, it appears that in order to prevent contamination, the endoscopic coupler must remain unitarily connected to the endoscope throughout the surgery. Thus, in order to be able to interchange endoscopes during the surgery, one has to utilize several endoscopic systems, each one having its own coupler and camera head. Thus, the use of the patented coupler tends to complicate the endoscopic proceeding rather than to simplify it.
Furthermore, since only the external section of the endoscopic system would be soaked prior to use, while the inner sections would not be sterilized, the uncoupling of the endoscope or the camera head during the surgical proceeding would increase the risk of contamination. An additional drawback of the patented coupler is its inability to be readily focused by the surgeon. Thus, in certain applications, the whole endoscopic system would have to be substituted with another endoscopic system. As a result, the surgical process is periodically disrupted, and is further rendered relatively complex and inefficient.
Therefore, it would be highly desirable to have a new and improved endoscopic adapter assembly for use in video endoscopy to couple an existing adapter to a corresponding camera head. The adapter assembly should substantially minimize, if not completely eliminate condensation on selected viewing optics of the endoscopic system, without compromising its sterility and effectiveness. It should further enable the interchangeability of endoscopes during the surgical procedure, and it should further be readily focusable. Additionally, the adapter assembly should be light in weight, compact, relatively simple to use, and inexpensive to produce.